CN116131624A

CN116131624A - Power supply circuit, power supply system and electronic device

Info

Publication number: CN116131624A
Application number: CN202310186732.3A
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Ensai Semiconductor Chengdu Co ltd
Current assignee: Ensai Semiconductor Chengdu Co ltd
Priority date: 2023-03-01
Filing date: 2023-03-01
Publication date: 2023-05-16

Abstract

The invention discloses a power supply circuit, a power supply system and an electronic device, wherein the power supply circuit comprises: the first end of the auxiliary winding is coupled with the first end of the input capacitor, or is coupled with the first end of the input capacitor after passing through a capacitor; a power supply capacitor configured to supply a power supply voltage for power supply; the auxiliary control module is coupled in series between the auxiliary winding and the power supply capacitor and at least comprises a normally-on high-voltage tube and a turn-off current source coupled in series with the normally-on high-voltage tube. The power supply circuit provided by the invention has the advantages of simple structure and high power supply efficiency.

Description

Power supply circuit, power supply system and electronic device

Technical Field

The present invention relates to the field of power conversion technologies, and in particular, to a power circuit, a power system, and an electronic device.

Background

Basically, each power supply system has its own power supply circuit, especially for the power supply system of the AC-DC power converter, since the bus voltage has a wide variation range, and generally includes the entire voltage range of 85Vac-265Vac, no matter the high voltage of the bus is applied to provide power for the driving chip of the power supply system through the resistor, the JFET or the high voltage MOSFET, the power supply efficiency of the entire power supply system is reduced, the temperature of the power supply system is increased, the volume is increased, and the cost is increased, so that improvement is necessary.

Disclosure of Invention

The embodiment of the invention provides a power supply circuit, a power supply system and an electronic device.

In a first aspect, an embodiment of the present invention provides a power supply circuit applied to a power supply system having a transformer, an input capacitor and an output capacitor, where the transformer has at least an auxiliary winding and a main winding, the power supply circuit includes:

the auxiliary winding is provided with two ends, and the first end of the auxiliary winding is coupled with the first end of the input capacitor or is coupled with the first end of the input capacitor after passing through a capacitor;

a power supply capacitor configured to supply a power supply voltage for power supply;

the auxiliary control module is coupled in series between the second end of the auxiliary winding and the power supply capacitor and at least comprises a normally-on high-voltage tube and a turn-off current source coupled in series with the normally-on high-voltage tube;

and controlling the auxiliary winding to flow current to charge the power supply capacitor or not to flow current by controlling the on or off of the turn-off current source.

Preferably, the power supply circuit is configured such that the current flowing through the auxiliary winding is conducted for a pulse time before the primary winding of the transformer starts to charge, so that the current flowing through the auxiliary winding flows through the current source to charge the power supply capacitor.

Preferably, the primary winding of the transformer is coupled in series with the first power switch, and before the first power switch is switched from the off state to the on state, the off current source is turned on for a pulse time, so that the current flowing through the auxiliary winding flows through the off current source and charges the power supply capacitor, the current flowing through the auxiliary winding is coupled to the primary winding of the transformer through the coupling action of the transformer, so that the voltage across the two ends of the first power switch is reduced from the initial first potential to the lower second potential, and then the first power switch is switched from the off state to the on state.

Preferably, the auxiliary control module of the power supply circuit comprises at least three ports, a first port being coupled to a second end of the auxiliary winding; a second port is coupled with the power supply capacitor; the third port is coupled to a second control signal that controls the turn-on or turn-off of the current source to cause the auxiliary winding to flow current and charge the supply capacitor or to cause the auxiliary winding to not flow current.

In a second aspect, an embodiment of the present invention provides a power supply system.

Preferably, the power supply system further comprises a load, a control module and a power stage coupled in parallel with the output capacitor; the power stage at least comprises a main stage winding of the transformer, a follow current module and a first power switch; the power supply circuit supplies power to the control module; the control module outputs a first control signal coupled to the control end of the first power switch and a second control signal coupled to the third port of the power circuit.

Preferably, the connection relation between the power stage and the input capacitor and the connection relation between the power stage and the output capacitor can be at least combined to form one power supply system of a buck power supply system, a boost power supply system, a flyback power supply system and a boost power supply system.

Preferably, before the control module controls the first power switch to switch from the off state to the on state, the control module controls the turn-off current source in the power circuit to conduct for a pulse time to charge the auxiliary winding, and after the voltage across the two ends of the first power switch coupled in series with the main winding is reduced from the initial first potential to the lower second potential through the coupling relation of the transformer, the control module controls the first power switch to switch from the off state to the on state.

Preferably, the transformers of the power supply system have the same-name end positions, and when a part or all of a pulse time is needed before the first power switch is switched from an off state to an on state, the current source can be turned off to be turned on, current flows into an auxiliary winding of the transformer and charges a power supply capacitor, and through the coupling relation between a main-stage winding and the auxiliary winding of the transformer, the voltage across the two ends of the first power switch is reduced from an initial first potential to a lower second potential, and then the first power switch is switched from the off state to the on state; or the transformer of the power supply system has opposite homonymous end positions, the current source can be turned off and turned on in a first period of pulse time before the first power switch is switched from the off state to the on state, current flows into an auxiliary winding of the transformer and charges a power supply capacitor, and the voltage across the two ends of the first power switch rises to a first potential; during the second period of the pulse time before the first power switch is switched from the off state to the on state, the current source can be turned off, and after the voltage across the two ends of the first power switch is reduced from the initial first potential to the lower second potential through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state.

Preferably, the power supply system comprises a driving chip, and the driving chip at least comprises an auxiliary control module and a control module; the power supply capacitor is positioned outside the driving chip; or the power supply capacitor is positioned in the driving chip; or the power supply capacitor is partially positioned outside the driving chip and partially positioned inside the driving chip.

In a third aspect, an embodiment of the present invention provides an electronic device, including the power supply circuit according to any one of the first aspects.

The technology of the invention has the following advantages:

according to the power supply circuit provided by the embodiment of the invention, the auxiliary winding for reducing the switching loss of the power supply system is multiplexed, and the auxiliary winding can bear the high voltage of the bus to supply power for the driving chip of the whole power supply system, so that the volume and the cost of the whole power supply system are reduced.

The power supply circuit adopting the technology of the invention has smaller area and lower cost.

Drawings

FIG. 1 is a simplified block diagram of a power circuit according to an embodiment of the present invention;

FIGS. 2a to 2e are block diagrams of a power supply system with a power supply circuit according to an embodiment of the present invention;

FIG. 3 is one embodiment of a normally-on high-pressure tube of the present invention;

Fig. 4a to 4b are schematic views of partial node waveforms according to some embodiments of the present invention.

Various features and elements are not drawn to scale in accordance with conventional practice in the drawings in order to best illustrate the specific features and elements associated with the invention. In addition, like elements/components are referred to by the same or similar reference numerals among the different drawings.

[ reference numerals description ]

11: first power supply system

100: first power stage

110: power supply circuit

1101: auxiliary control module

1102: power supply capacitor

11011: normally-on high-pressure pipe

112: control module

12: second power supply system

120: second power stage

121: freewheel module

13: third power supply system

130: third power stage

14: fourth power supply system

140: fourth power stage

141: absorption circuit

15: fifth power supply system

150: fifth power stage

16: sixth power supply system

160: sixth power stage

[ symbolic description ]

MP: first power switch

MA: current source capable of being turned off

GP: first control signal

GA: second control signal

Vds: cross-over pressure

P1: first port

P2: second port

P3: third port

Ts: transformer

Lp: main-stage winding

Ls: secondary winding

La: auxiliary winding

Ip: main stage winding current

Ia: auxiliary winding current

Is: secondary winding current

Nps: turns ratio

Dlp: absorption diode

Clp: absorption capacitor

VCC: supply voltage

CIN: input capacitance

CO: output capacitor

VIN: input voltage

VO: load voltage

HSD: high voltage end

LSD: low voltage end

T1-T3: time point

T12: during a first period

T23: second period

T13: pulse time.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In a first aspect, an embodiment of the present invention provides a power supply circuit.

As shown in fig. 1, a power supply circuit 110 is applied to a power supply system 11 having a transformer Ts, an input capacitance CIN, and an output capacitance CO, the transformer Ts having at least an auxiliary winding La and a main stage winding Lp, the power supply circuit 110 comprising: the auxiliary winding La has two ends, and the first end is coupled to the input voltage VIN of the first end of the input capacitor CIN or is coupled to the input voltage VIN of the first end of the input capacitor CIN after passing through a capacitor; a supply capacitor 1102 configured to supply a supply voltage VCC for supplying power; an auxiliary control module 1101 coupled in series between the second end of the auxiliary winding La and the supply capacitor 1102, comprising at least a switchable current source MA; by controlling the on or off state of the off current source MA, the auxiliary winding La is controlled to flow a current to charge the power supply capacitor 1102 or not.

In one embodiment, as shown in fig. 1, the power circuit 1101 may switch off the current source MA for a pulse time before the primary winding Lp of the transformer Ts starts to charge, so that the current flowing through the auxiliary winding La flows through the current source MA and charges the power supply capacitor VCC.

In one embodiment, the primary winding Lp of the transformer Ts is coupled in series with the first power switch MP, and in one embodiment, the primary winding Lp is coupled to a first end of the first power switch MP; in one embodiment, the main stage winding Lp is coupled with a second end of the first power switch MP; before the first power switch MP is switched from the off state to the on state (or before the main winding Lp of the transformer Ts starts to charge), the off current source MA is turned on for a pulse time, so that the current flowing through the auxiliary winding La flows through the off current source MA and charges the power supply capacitor 1102, the current flowing through the auxiliary winding La is coupled to the main winding Lp of the transformer Ts through the coupling action of the transformer Ts, so that the voltage across Vds across the first power switch MP is reduced from the initial first potential to the lower second potential, and then the first power switch MP is switched from the off state to the on state (or the main winding Lp of the transformer Ts starts to charge again). In one embodiment, as shown in fig. 1, the auxiliary control module 1101 of the power circuit 110 includes at least three ports, a first port P1 being coupled to a second end of the auxiliary winding La; the second port P2 is coupled to the supply capacitor 1102; the third port P3 is coupled to a second control signal GA, which controls the turn-on or turn-off of the current source MA, so that the auxiliary winding La flows current and charges the supply capacitor 1102, or so that the auxiliary winding La does not flow current.

In one embodiment, as shown in fig. 1, the first port P1 of the auxiliary control module 1101 is coupled to a first end of the normally-on high voltage tube 11011, a second end of the normally-on high voltage tube 11011 is coupled to a first end of the off current source MA, the second port P2 is coupled to a second end of the off current source MA, and the third port P3 is coupled to a control end of the off current source MA.

In one embodiment, as shown in fig. 3, the normally-on high voltage tube 11011 includes a junction field effect tube JFET (or a depletion field effect tube MOSFET), and the high voltage end HSD of the normally-on high voltage tube 11011 is coupled to the second end of the auxiliary winding La or the first port P1 of the auxiliary control module 1101; the low voltage end LSD of the normally-on high voltage tube 11011 is coupled with the first end of the turn-off current source MA; the control terminal CG of the normally-on high voltage pipe 11011 is coupled to ground (or to a fixed level), and since the normally-on high voltage pipe 11011 is also in a conductive state when the control terminal CG is coupled to ground, the current flowing through the normally-on high voltage pipe 11011 is completely controlled by the switchable current source MA coupled in series therewith. When the off current source MA is turned on, a current flowing through the off current source MA flows through the auxiliary winding La and the normally-on high voltage tube 11011; when the off-state current source MA is off, no current flows through the auxiliary winding La and the normally-on high-voltage tube 11011; the main function of the normally-on high voltage tube 11011 is to isolate the high voltage between the off current source MA and the second end of the auxiliary winding La. The current source MA can be turned off in the prior art, and the enable control terminal is added to the current source, and the current source is controlled to be turned on or off to generate no current by the enable control signal of the enable control terminal, so that the detailed description will not be given in the specification.

In one embodiment, as shown in fig. 1, the first power supply system 11 further includes a load coupled in parallel with the output capacitor CO, the control module 112, and the first power stage 100; the first power stage 100 comprises at least a main stage winding Lp of a transformer Ts, a freewheel module 121 and a first power switch MP; the power circuit 110 supplies power to the control module 112; the control module 112 outputs a first control signal GP coupled to the control terminal of the first power switch MP and a second control signal GA coupled to the third port P3 of the auxiliary control module 1101.

In one embodiment, as shown in fig. 1, the connection relationship between the first power stage 100 of the first power supply system 11 and the input capacitor CIN and the output capacitor CO may be at least combined to form one of a Buck power supply system (Buck), a Boost power supply system (Boost), a Flyback power supply system (Flyback), and a Buck Boost power supply system (Buck Boost).

In one embodiment, as shown in fig. 1, before the control module 112 controls the first power switch MP to switch from the off state to the on state (or before the main winding Lp of the transformer Ts starts to charge), the control module 112 controls the turn-off current source MA in the power supply circuit 110 to lead a part or all of a pulse time to charge the auxiliary winding La, and after the voltage across Vds across the first power switch MP coupled in series with the main winding Lp is reduced from the initial first potential to the lower second potential through the coupling relationship of the transformer Ts, the control module 112 controls the first power switch MP to switch from the off state to the on state (or the main winding Lp of the transformer Ts starts to charge again); in one embodiment, a first end of the main stage winding Lp is coupled to a first end of the first power switch MP, and a second end of the first power switch MP is grounded; in one embodiment, the first terminal of the main stage winding Lp is coupled to the second terminal of the first power switch MP, and the first terminal of the first power switch MP is coupled to the input voltage VIN of the first terminal of the input capacitor CIN.

In one embodiment, as shown in fig. 1, the transformers Ts of the first power system 11 have the same-name end positions, and after a part or all of a pulse time before the first power switch MP is switched from the off state to the on state, the current source MA is turned off, current flows into the auxiliary winding La of the transformers Ts and charges the power supply capacitor 1102, and the voltage across Vds of both ends of the first power switch MP is reduced from the initial first potential to the lower second potential through the coupling relationship between the main winding Lp and the auxiliary winding La of the transformers Ts, and then the first power switch MP is switched from the off state to the on state.

In one embodiment, as shown in fig. 1, the transformer Ts of the first power supply system 11 has opposite identical-name end positions, and during a first period of a pulse time before the first power switch MP is switched from the off state to the on state, the off-current source MA is turned on, a current flows into the auxiliary winding La of the transformer Ts and charges the power supply capacitor 1102, and the voltage across Vds of the first power switch MP rises to the first potential; during a second period of the pulse time before the first power switch MP is switched from the off state to the on state, the off current source MA is turned off, and the voltage across Vds across the first power switch MP is reduced from the initial first potential to the lower second potential through the coupling relationship between the main winding Lp and the auxiliary winding La of the transformer Ts, and then the first power switch MP is switched from the off state to the on state.

The homonymous ends of the two windings of the transformer are defined as follows: when current flows into (or out of) two windings simultaneously from one end of each winding respectively, if magnetic fluxes generated by the two windings are aided, the two ends are called as homonymous ends of the transformer winding, and black dots "·" or asterisks are used for marking. The positions of the homonymous terminals can be defined by themselves, the inflow terminals can be called homonymous terminals, and the outflow terminals can be called homonymous terminals.

In one embodiment, the first power system 11 further includes a rectifier bridge, an input terminal of the rectifier bridge is coupled to the ac power, and an input capacitor CIN is coupled to an output terminal of the rectifier bridge, for bypassing the high frequency signal; in one embodiment, the input terminal of the first power system 11 is directly coupled to the dc input voltage VIN, and the input capacitor CIN is used for bypassing the high frequency signal of the input voltage VIN.

In one embodiment, the freewheel module 121 is composed of diodes, and the power stages including the diodes constitute an asynchronous rectification structure.

In one embodiment, the freewheel module 121 is composed of a field effect transistor (MOSFET), and the power stage including the field effect transistor constitutes a synchronous rectification structure.

In one embodiment, as shown in fig. 1, the first power system 11 includes a driver chip including at least an auxiliary control module 1101 and a control module 112; in one embodiment, the supply capacitor 1102 is located external to the driver chip; in one embodiment, the supply capacitor 1102 is located inside the driver chip; in one embodiment, the supply capacitor 1102 is located partially outside the driver chip and partially inside the driver chip.

In one embodiment, as shown in fig. 2a, the second power supply system 12 includes an input capacitance CIN, a load coupled in parallel with an output capacitance CO, a power supply circuit 110, a control module 112, and a second power stage 120, the second power stage 120 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; a first terminal of the output capacitor CO is coupled to a first terminal of the input capacitor CIN and a second terminal of the freewheel module 121; the second terminal of the input capacitor CIN is coupled with the ground; the homonymous end of the auxiliary winding La is coupled with the homonymous end of the main stage winding Lp and the second end of the output capacitor CO; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN after passing through the output capacitor CO, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary control module 1101; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the freewheel module 121; the control end of the first power switch MP is coupled to the first control signal GP output by the control module 112; the power circuit 110 provides power to the control module 112.

The second power supply system 12 belongs to a step-down power supply system, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp through the load and the output capacitor CO, at this time, the voltage drop on the main winding Lp is approximately VIN-VO (neglecting the conduction voltage drop of the first power switch MP), and by the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is also kept to be VIN-VO or approximately equal to VIN-VO when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (VIN-VO) - (VIN-VO) =0; when the first power switch MP is turned off, the load voltage VO on the output capacitor CO discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately-VO, and by the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is also maintained to be-VO or approximately equal to-VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (VIN-VO) - (-VO) =vin.

In combination with the waveform schematic diagram shown in fig. 4a and the structure diagram of the second power supply system 12 shown in fig. 2a, before the first control signal GP controlled by the control module 112 is turned to high level to control the first power switch MP to be turned on, the second control signal GA outputted by the control module 112 first generates a high level pulse time T13, so that the turn-off current source MA in the auxiliary control module 1101 is turned on for a pulse time T13 to charge the auxiliary winding La, the auxiliary winding current Ia flowing through the auxiliary winding La flows through the turn-off current source MA to charge the supply capacitor 1102, the current flowing through the auxiliary winding La is coupled to the main winding Lp through the coupling relationship of the transformer Ts to generate a main winding current Ip with opposite direction, in the pulse time T13 when the current source MA is turned on, the auxiliary winding current Ia and the main winding current Ip with opposite directions are generated on the secondary winding La correspondingly, the main winding current Ip generated by coupling transfers the charge on the parasitic capacitance Cds of the first power switch MP coupled in series with the main winding to the main winding Lp, so that the voltage across Vds of the first power switch MP is reduced, the voltage across Vds of the first power switch MP is reduced from the initial first potential VIN (neglecting the conduction voltage drop on the flywheel module 121) to the second potential (such as zero potential or a potential close to zero potential) lower than VIN, and then the first control signal GP output by the control module 112 becomes high level to control the first power switch MP to switch from the off state to the on state.

In the waveform diagram shown in fig. 4a, the time point T1 corresponds to a time point when the turn-off current source MA is turned on in preference to the first power switch MP, and in one embodiment, the time point T1 is generated in response to the demagnetization end signal of the transformer; in one embodiment, the T1 time point is generated in response to a trough of the voltage across the first power switch MP Vds (either the first trough or the nth trough); in one embodiment, the T1 time point is generated in response to a pulse width modulated signal (PWM signal) of the second power supply system 12.

In the waveform schematic shown in fig. 4a, the time point T3 corresponds to the on time point of the first power switch MP, the period between the time point T1 and the time point T3 is the pulse time T13 for turning on the turn-off current source MA, the length of the pulse time T13 and the magnitude of the auxiliary winding current Ia flowing through the auxiliary winding La determine the amplitude of the voltage across the first power switch MP from the initial first potential VIN to the lower second potential, and in one embodiment, the pulse time T13 and the auxiliary winding current Ia are optimized such that the second potential approaches zero potential, and then the first power switch MP is turned on again to realize the switching of the first power switch MP in the zero voltage state;

In the waveform diagram shown in fig. 4a, the time point T3 is also the off time point of the current source MA, and is also the on time point of the first power switch MP, in one embodiment, the off time point of the current source MA is a time point T2 (the time point T2 is not shown in fig. 4 a) between the time point T1 and the time point T3, and the current source MA is not turned on during the whole pulse time T13, but is turned on only during the first period T12 of the pulse time T13, and is turned off during the second period T23.

In one embodiment, as shown in fig. 2b, the third power supply system 13 also belongs to a step-down power supply system, and the difference between the third power supply system 13 and the second power supply system 12 is that the same-name end positions of the transformers Ts are different, the transformers Ts in the second power supply system 12 have the same-name end positions, and the transformers Ts in the third power supply system 13 have different same-name end positions.

The third power supply system 13 comprises an input capacitor CIN, a load coupled in parallel with an output capacitor CO, a power supply circuit 110, a control module 112 and a third power stage 130, the third power stage 130 comprising a main stage winding Lp, a freewheel module 121 and a first power switch MP; a first terminal of the output capacitor CO is coupled to a first terminal of the input capacitor CIN and a second terminal of the freewheel module 121; the second terminal of the input capacitor CIN is coupled with the ground; the homonymous end of the auxiliary winding La is coupled with the non-homonymous end of the main-stage winding Lp and the second end of the output capacitor CO; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN after passing through the output capacitor CO, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary control module 1101; the homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the freewheel module 121; the control end of the first power switch MP is coupled to the first control signal GP output by the control module 112; the power circuit 110 provides power to the control module 112.

In the third power supply system 13, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp through the load and the output capacitor CO, and at this time, the voltage drop on the main winding Lp is approximately VIN-VO (neglecting the conduction voltage drop of the first power switch MP), and by virtue of the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is kept to be- (VIN-VO) or approximately equal to- (VIN-VO) when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (VIN-VO) + (VIN-VO) =2 (VIN-VO); when the first power switch MP is turned off, the load voltage VO on the output capacitor CO discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately-VO, and by means of the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is also kept at VO or approximately equal to VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (VIN-VO) -vo=vin-2 VO.

In combination with the waveform schematic diagram shown in fig. 4b and the structure diagram of the third power supply system 13 shown in fig. 2b, before the control module 112 controls the output first control signal GP to become high level to control the first power switch MP to be turned on, the second control signal GA output by the control module 112 generates a high level in the first period T12 of the pulse time T13, the auxiliary winding La is charged by the turn-off current source MA in the auxiliary control module 1101 in the first period T12 of the pulse time, the power supply capacitor 1102 is charged by the auxiliary winding current Ia flowing through the auxiliary winding La through the turn-off current source MA, the current flowing through the auxiliary winding La is coupled to the primary winding Lp through the coupling relation of the transformer Ts, the voltage of the primary winding Ip with the same direction is generated, the voltage of the cross-voltage Vds across the first power switch MP is raised to the first VIN potential (the conduction voltage drop on the freewheel module 121 is ignored), in the schematic diagram shown in fig. 4b, the first period T12 of the pulse time T13 is high level, the corresponding current of the auxiliary winding La flows through the turn-off current source MA to charge the power capacitor 1102, the corresponding current flowing through the auxiliary winding La in the same direction as the secondary winding La is generated by the first voltage of the primary winding Ip, and the voltage of the primary winding Ip is coupled to the first voltage of the primary winding is connected in series with the first voltage potential of the primary winding with the same direction; in the second period T23 of the pulse time T13, the second control signal GA is at a low level, the turn-off current source MA is turned off, and the voltage across Vds across the first power switch MP is rapidly reduced from the initial first potential VIN to a lower second potential (for example, a zero potential or a potential close to zero) in the second period T23 through the coupling relationship between the main winding Lp and the auxiliary winding La of the transformer Ts, so that the first control signal GP output by the control module 112 becomes at a high level, and the first power switch MP is controlled to switch from the off state to the on state.

In the waveform diagram shown in fig. 4b, the time point T1 corresponds to a time point when the turn-off current source MA is turned on in preference to the first power switch MP, and in one embodiment, the time point T1 is generated in response to the demagnetization end signal of the transformer; in one embodiment, the T1 time point is generated in response to a trough of the voltage across the first power switch MP Vds (either the first trough or the nth trough); in one embodiment, the T1 time point is generated in response to a pulse width modulated signal (PWM signal) of the third power supply system 13.

In the waveform diagram shown in fig. 4b, the time point T3 corresponds to the on time point of the first power switch MP, the first period T12 between the time point T1 and the time point T2 is the pulse time for turning off the current source MA, the length of the first period T12, the length of the second period T23, and the magnitude of the auxiliary winding current Ia flowing through the auxiliary winding La determine the amplitude of the voltage across the first power switch MP from the initial first potential VIN to the lower second potential, and in one embodiment, the three parameters are optimized to make the second potential approach zero potential, and then the first power switch MP is turned on again to realize the switching of the first power switch MP in the zero voltage state.

In one embodiment, as shown in fig. 2c, the fourth power supply system 14 includes an input capacitor CIN, a load coupled in parallel with an output capacitor CO, a power supply circuit 110, a control module 112, a fourth power stage 140 and an absorption circuit 141, the fourth power stage 140 including a primary winding Lp and a secondary winding Ls of a transformer Ts, a freewheel module 121 and a first power switch MP; the snubber circuit 141 includes a snubber diode Dlp and a snubber capacitor Clp; the first end of the input capacitor CIN is coupled with the same-name end of the main-stage winding Lp and the second end of the absorption capacitor Clp, the second end of the input capacitor CIN is coupled with the ground, the first end of the absorption capacitor Clp is coupled with the same-name end of the auxiliary winding La and the cathode of the absorption diode Dlp, the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN after passing through the absorption capacitor Clp, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary control module 1101; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the anode of the absorption diode Dlp, and the control end of the first power switch MP is coupled with a first control signal GP output by the control module 112; the first end of the output capacitor CO is coupled with the second end of the follow current module 121, the first end of the follow current module 121 is coupled with the non-homonymous end of the secondary winding Ls, and the homonymous end of the secondary winding Ls is coupled with the second end of the output capacitor CO; or the first end of the output capacitor CO is coupled with the non-homonymous end of the secondary winding Ls, the second end of the output capacitor CO is coupled with the first end of the freewheel module 121, and the second end of the freewheel module 121 is coupled with the homonymous end of the secondary winding Ls; the power circuit 110 provides power to the control module 112.

The fourth power supply system 14 belongs to a flyback power supply system, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on-voltage drop of the first power switch MP), and by the coupling relationship of the transformer Ts, the voltage drop across the auxiliary winding La is also kept at VIN or approximately VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (vin+ Nps ×vo) -vin= Nps ×vo, (Nps is the turns ratio of the primary winding Lp to the secondary winding Ls); when the first power switch MP Is turned off, the load voltage VO on the output capacitor CO discharges the secondary winding Ls, and the secondary winding current Is generated to charge the output capacitor CO, which Is equivalent to the voltage drop on the primary winding Lp being approximately-Nps ×vo (neglecting the on-voltage drop of the snubber diode Dlp), and the voltage at the first port P1 of the auxiliary control module 1101 Is (vin+ Nps ×vo) - (-Nps ×vo) =vin+2mps×vo during the secondary winding Ls discharge.

The operation principle of the power circuit 110 in the fourth power system 14 and the operation principle of implementing that the first power switch MP operates in the zero-voltage switching state are identical to each other compared to the second power system 12, and the description will not be repeated.

In one embodiment, the homonymous terminal of the auxiliary winding La in the fourth power supply system 14 may also be coupled to a first terminal of the input capacitance CIN.

In one embodiment, as shown in fig. 2d, the fifth power supply system 15 includes an input capacitor CIN, a load coupled in parallel with an output capacitor CO, a power supply circuit 110, a control module 112, and a fifth power stage 150, the fifth power stage 150 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; the second end of the output capacitor CO is coupled with the first end of the input capacitor CIN, the homonymous end of the main-stage winding Lp and the homonymous end of the secondary winding La; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary control module 1101; the second terminal of the input capacitor CIN is coupled with the ground; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the freewheel module 121; the second end of the freewheel module 121 is coupled to the first end of the output capacitor CO, and the control end of the first power switch MP is coupled to the first control signal GP output by the control module 112; the power circuit 110 provides power to the control module 112.

The fifth power supply system 15 belongs to a step-up/down power supply system, and when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, and at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on voltage drop of the first power switch MP), and by means of the coupling relationship of the transformer Ts, the voltage drop across the auxiliary winding La is also kept at VIN or approximately VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is VIN-vin=0; when the first power switch MP is turned off, the load voltage VO on the output capacitor CO discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately-VO, and by the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is also maintained to be-VO or approximately equal to-VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is VIN- (-VO) =vin+vo.

The operation principle of the power circuit 110 in the fifth power system 15 and the operation principle of implementing that the first power switch MP operates in the zero-voltage switching state are identical to those of the second power system 12, and the description will not be repeated.

In one embodiment, the homonymous terminal of the auxiliary winding La in the fifth power supply system 15 may also be coupled to the first terminal of the output capacitance CO.

In one embodiment, as shown in fig. 2e, the sixth power system 16 includes an input capacitance CIN, a load coupled in parallel with an output capacitance CO, a power circuit 110, a control module 112, and a sixth power stage 160, the sixth power stage 160 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; the first end of the input capacitor CIN is coupled with the homonymous end of the main stage winding Lp and the homonymous end of the secondary winding La; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary control module 1101; the second terminal of the input capacitor CIN is coupled with the ground; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the freewheel module 121; the second end of the freewheel module 121 is coupled to the first end of the output capacitor CO, the second end of the output capacitor CO is coupled to ground, and the control end of the first power switch MP is coupled to the first control signal GP output by the control module 112; the power circuit 110 provides power to the control module 112.

The sixth power supply system 16 belongs to a boost power supply system, and when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on-voltage drop of the first power switch MP), and by means of the coupling relationship of the transformer Ts, the voltage drop across the auxiliary winding La is also kept at VIN or approximately equal to VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is VIN-vin=0; when the first power switch MP is turned off, the difference between the load voltage VO on the output capacitor CO and the input voltage VIN discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately VO-VIN, and by means of the coupling relationship of the transformer Ts, the voltage drop on the auxiliary winding La is also kept at VO-VIN or approximately equal to VO-VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is vin+ (VO-VIN) =vo.

The operation principle of the power circuit 110 in the sixth power system 16 and the operation principle of implementing the first power switch MP to operate in the zero-voltage switching state are identical to those of the second power system 12, and the description will not be repeated.

In one embodiment, the homonymous terminal of the auxiliary winding La in the sixth power supply system 16 may also be coupled to the first terminal of the output capacitance CO.

In the above embodiments, in order to conveniently, more clearly and simply describe the working principle of the present invention, the description only exemplifies the case that the number of turns of the main winding Lp and the auxiliary winding La of the transformer Ts is the same, and in the practical implementation process, the number of turns of the main winding Lp and the auxiliary winding La of the transformer Ts may be kept different, but the working principle of the present invention is not affected.

From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

1) The power supply circuit of the utility model multiplexes the auxiliary winding that reduces the switching loss of the power supply system to can let the auxiliary winding bear the high voltage of generating line and provide electric power for the drive chip of whole power supply system, reduce whole power supply system's volume and cost.

2) The electronic device provided by the application multiplexes the auxiliary winding for reducing the switching loss of the power supply system, and can enable the auxiliary winding to bear the high voltage of the bus to provide power for the driving chip of the whole power supply system, thereby reducing the volume and the cost of the whole power supply system.

It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.

It should also be noted that, in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements to be referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Moreover, relational terms such as "first" and "second" may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions, or order, and without necessarily being construed as indicating or implying any relative importance. "and/or" means either or both of which may be selected. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or terminal device comprising the element.

The foregoing has outlined rather broadly the more detailed description of the invention in order that the detailed description of the invention that follows may be better understood, and in order that the present contribution to the art may be better appreciated. While various modifications of the embodiments and applications of the invention will occur to those skilled in the art, it is not necessary and not intended to be exhaustive of all embodiments, and obvious modifications or variations of the invention are within the scope of the invention.

Claims

1. A power circuit for use in a power system having a transformer, an input capacitor and an output capacitor, the transformer having at least an auxiliary winding and a primary winding, the power circuit comprising:

2. The power circuit of claim 1, wherein the off-state current source is turned on for a pulse time before the primary winding of the transformer begins to charge, such that the current flowing through the auxiliary winding flows through the off-state current source to charge the supply capacitor.

3. The power circuit of claim 1, wherein the primary winding of the transformer is coupled in series with the first power switch, the turn-off current source is turned on for a pulse time before the first power switch is switched from the off state to the on state, the current flowing through the auxiliary winding is charged to the power supply capacitor after flowing through the turn-off current source, the current flowing through the auxiliary winding is coupled to the primary winding of the transformer through the coupling action of the transformer, and the first power switch is switched from the off state to the on state after the voltage across the first power switch is reduced from the initial first potential to the lower second potential.

4. The power circuit of claim 1, wherein the auxiliary control module of the power circuit comprises at least three ports, a first port coupled with a second end of the auxiliary winding; a second port is coupled with the power supply capacitor; the third port is coupled to a second control signal that controls the turn-on or turn-off of the current source to cause the auxiliary winding to flow current and charge the supply capacitor or to cause the auxiliary winding to not flow current.

5. A power supply system comprising at least the power supply circuit of any one of claims 1 to 4, further comprising a load, a control module, and a power stage coupled in parallel with the output capacitance; the power stage at least comprises a main stage winding of the transformer, a follow current module and a first power switch; the power supply circuit supplies power to the control module; the control module outputs a first control signal coupled to the control end of the first power switch and a second control signal coupled to the third port of the power circuit.

6. The power system of claim 5, wherein the connection between the power stage and the input capacitor and the output capacitor is at least one of a buck power system, a boost power system, a flyback power system, and a buck-boost power system.

7. The power supply system according to claim 5, wherein the control module controls the turn-off current source in the power supply circuit to be turned on for a pulse time to charge the auxiliary winding before the first power switch is switched from the off state to the on state, and controls the first power switch to be switched from the off state to the on state after the voltage across the first power switch serially coupled to the primary winding is reduced from the initial first potential to the lower second potential through the coupling relation of the transformer.

8. The power supply system of claim 7, wherein the transformers of the power supply system have identical end positions, and the current source is turned off for a part or all of a pulse time before the first power switch is switched from the off state to the on state, current flows into the auxiliary winding of the transformer and charges the power supply capacitor, and the voltage across the first power switch is switched from the off state to the on state after the voltage across the first power switch is reduced from the initial first potential to the lower second potential through the coupling relationship between the main winding and the auxiliary winding of the transformer; or the transformer of the power supply system has opposite homonymous end positions, the current source can be turned off and turned on in a first period of pulse time before the first power switch is switched from the off state to the on state, current flows into an auxiliary winding of the transformer and charges a power supply capacitor, and the voltage across the two ends of the first power switch rises to a first potential; during the second period of the pulse time before the first power switch is switched from the off state to the on state, the current source can be turned off, and after the voltage across the two ends of the first power switch is reduced from the initial first potential to the lower second potential through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state.

9. The power system of claim 5, wherein the power system comprises a driver chip including at least an auxiliary control module and a control module; the power supply capacitor is positioned outside the driving chip; or the power supply capacitor is positioned in the driving chip; or the power supply capacitor is partially positioned outside the driving chip and partially positioned inside the driving chip.

10. An electronic device comprising the power supply circuit of any one of claims 1 to 4.